* Home centers sell sand for sand boxes, landscaping, paving, mortar etc. Beaches are another source, although you may encounter undesirable contamination. Sifting non-homogeneous sand with a fine kitchen strainer may yield two usable grades of sand.

** secondary containment to prevent accidental spillage of water onto the balance

Background Soil Vocabulary:

Porosity is the measure of how much groundwater a soil can hold, permeability is the measure of how quickly water passes through a soil, while retention is the measure of how much water stays behind. Even elementary students can relate these concepts to their everyday lives. They observe that some areas in their yards or school grounds form puddles while others drain quickly after a rainstorm. They may wonder why one neighbor’s garden and yard remains lush and green although a sprinkler is rarely used. Children in communities dependent upon well water can understand the importance of replenishing the water table. In most rural and many suburban areas, homes use septic tanks and drain fields to process household wastewater. The “water cycle” is a topic in elementary science curricula. There are many excellent age-appropriate online sources for information on these topics including the United States Geological Survey (USGS) and the GLOBE program. Read the rest of this entry »